Flow control valves are used to control fluid flow rates in a variety of applications. One particular application relates to controlling a fluid (e.g. gas or liquid) flow in a pneumatic test apparatus when testing various pneumatic pressure systems or components that are to be installed on an aircraft. By way of example, one type of pneumatic test apparatus is an air data tester (ADT), which is often employed in ground testing aircraft aerospace systems or components. One type of aerospace test system simulates in-flight air pressures to supply pneumatic data to an aircraft control and display avionics system, which in turn provides data regarding the aircraft's altitude, vertical speed, airspeed, Mach number, etc.
The flow control valve must be capable of precisely duplicating in-flight pneumatic pressures normally encountered by an aircraft over its entire flight profile. Existing valves, such as those described in U.S. Pat. Nos. 4,131,130 and 6,202,669 are generally complex assemblies that are sensitive to a number of individual part tolerances between nozzle orifices. The valves described in the identified patents include an electromagnetic torque motor for moving a flapper mechanism relative to a nozzle orifice of a pressure fitting. Due to the complexity of the assemblies and the interrelated mechanical tolerance sensitivity, the aforementioned valves are difficult to manufacture in large quantities in a short period of time. In addition, the complex assembly increases cost.